Nikita Kamaev, the former executive director of the Russian Anti-Doping Agency (RUSADA), died in his home on Sunday. His death, which happened after Kamaev returned from vacation, was allegedly caused by a heart attack, according to Bloomberg Business.

The 52-year-old RUSADA chief's death had been confirmed by his former peers at the agency, with former RUSADA general director Ramil Khabriev stating that Kamaev was at home when he started feeling chest pains.

"I've been told that he was out cross-country skiing, came home, and felt pain in the area of the heart. I'd never heard him complain of anything to do with his heart. Perhaps his wife knew about some sort of problem," he said, according to The Daily Mail.

Kamaev's death comes two months after he, together with other executives such as Khabriev, quit his post on RUSADA, amid the Russian Sports Ministry's drive to initiate a series of reforms in its leadership.

RUSADA had previously been embroiled in an issue with the World Anti-Doping Agency after the international organization demanded that the Russian agency stop conducting drug tests over allegations that RUSADA was not being compliant with anti-doping rules, reports BBC News.

Kamaev's death comes less than two weeks after another ex-RUSADA figure, Vyacheslav Sinev, who left the agency back in 2010, died on Feb. 3.